JP6508447B1 - Method of manufacturing RTB based sintered magnet - Google Patents

Abstract

A method of producing an RTB-based sintered magnet according to the present disclosure comprises the steps of: preparing an R1-T1-B-based sintered body; preparing an R2-Ga-Cu-Co-based alloy; Contacting at least a portion of the alloy with at least a portion of the surface of the body and performing a first heat treatment at a temperature of 700 ° C. or more and 1100 ° C. or less in a vacuum or an inert gas atmosphere; And performing a second heat treatment at a temperature of 450 ° C. or more and 600 ° C. or less in a vacuum or an inert gas atmosphere with respect to the implemented R1-T1-B-based sintered body. R1 and R2 are at least one of rare earth elements and always contain at least one of Nd and Pr. The molar ratio of T1 to B ([T1] / [B]) is more than 14.0 and 15.0 or less.

Description

  The present invention relates to a method of producing an RTB-based sintered magnet.

  R-T-B based sintered magnet (R is at least one of rare earth elements. T is at least one of transition metal elements and necessarily contains Fe. B is boron.) Is a permanent magnet. It is known as the most powerful magnet, and is used for voice coil motor (VCM) of hard disk drive, electric motor (EV, HV, PHV etc.) motor for electric car, various motors such as motor for industrial equipment, home electric appliance etc. There is.

The RTB-based sintered magnet is mainly composed of a main phase consisting mainly of an R ₂ T ₁₄ B compound and a grain boundary phase located at the grain boundary part of this main phase (hereinafter sometimes referred to simply as “grain boundary”). It is configured. The R ₂ T ₁₄ B compound is a ferromagnetic phase having high magnetization, and forms the basis of the characteristics of the RTB-based sintered magnet.

The _RTB -based sintered magnet has a problem that irreversible heat demagnetization occurs because the coercivity H _cJ (hereinafter, sometimes simply referred to as "coercive force" or "H _cJ ") decreases at high temperature. Therefore, in a particularly R-T-B based sintered magnet used in an electric vehicle motor, having a high H _cJ even at high temperatures, that is, required to have a higher H _cJ at room temperature.

In the RTB-based sintered magnet, part of the light rare earth elements (mainly Nd and / or Pr) contained in R in the R ₂ T ₁₄ B compound is a heavy rare earth element (mainly Dy and / or Tb) It is known that substitution improves H _cJ . H _cJ improves as the substitution amount of heavy rare earth elements increases.

However, replacing the light rare earth element in the R ₂ T ₁₄ B compound with a heavy rare earth element improves H _{cJ of the RTB} -based sintered magnet, while the residual magnetic flux density B _r (hereinafter simply referred to as “B _r ” May fall down). In addition, heavy rare earth elements, in particular Dy, etc., have a problem that supply is not stable due to a small amount of resources and limited production areas, and the price fluctuates significantly. Therefore, in recent years, the user is required to improve H _cJ without using heavy rare earth elements as much as possible.

Patent Document 1 discloses an RTB-based rare earth sintered magnet in which the coercive force is increased while the content of Dy is reduced. The composition of this sintered magnet is limited to a specific range in which the amount of B is relatively small compared to the R-T-B based alloy generally used, and is selected from Al, Ga, and Cu 1 It contains metal element M of a species or more. As a result, R ₂ T ₁₇ phase is produced in the grain boundary, by the volume ratio of the R ₂ T ₁₇ transition metal-rich phase formed in the grain boundary from phase (R ₆ T ₁₃ M) increases, H _cJ Improve.

International Publication No. 2013/008756

The method described in Patent Document 1 is noteworthy in that the coercivity of the RTB-based sintered magnet can be increased while suppressing the content of heavy rare earth elements. However, there is a problem that B _r is greatly reduced. Also, in recent years, _RTB -based sintered magnets having higher H _cJ have been required in applications such as motors for electric vehicles.

Embodiments of the present disclosure, while reducing the content of heavy rare earth elements, to provide a method of manufacturing a R-T-B based sintered magnet having a high B _r and a high H _cJ.

  The manufacturing method of the RTB-based sintered magnet of the present disclosure is, in a non-limiting exemplary embodiment, preparing an R1-T1-B-based sintered body, R2-Ga-Cu-Co, and And preparing at least a part of the R2-Ga-Cu-Co alloy on at least a part of the surface of the R1-T1-B sintered body, in a vacuum or inert gas atmosphere. And a step of performing the first heat treatment at a temperature of 700 ° C. or more and 1100 ° C. or less, and a vacuum or inert gas atmosphere for the R1-T1-B based sintered body for which the first heat treatment is performed. And performing a second heat treatment at a temperature of 450 ° C. or more and 600 ° C. or less. In the R1-T1-B-based sintered body, R1 is at least one of rare earth elements and always contains at least one of Nd and Pr, and the content of R1 is that of the entire R1-T1-B-based sintered body. 27 mass% or more and 35 mass% or less, T1 is at least one selected from the group consisting of Fe, Co, Al, Mn, and Si, T1 always contains Fe, and the Fe content relative to the entire T1 is It is 80 mass% or more, and the molar ratio of T1 to B ([T1] / [B]) is more than 14.0 and 15.0 or less. In the R2-Ga-Cu-Co alloy, R2 is at least one of rare earth elements and necessarily contains at least one of Nd and Pr, and the content of R2 is the entire R2-Ga-Cu-Co alloy. 35 mass% or more and less than 85 mass%, the content of Ga is 2.5 mass% or more and 30 mass% or less of the entire R2-Ga-Cu-Co alloy, the content of Cu is R2-Ga-Cu-Co 2.5 mass% or more and 20 mass% or less of the entire alloy, the content of Co is more than 10 mass% and 45 mass% or less of the whole R2-Ga-Cu-Co alloy, the content of R2> the content of Co > Ga content> Cu content inequality is satisfied.

  In one embodiment, the molar ratio of T to B ([T1] / [B]) is 14.5 or more and 15.0 or less.

  In one embodiment, 50 mass% or more of R2 in the R2-Ga-Cu-Co-based alloy is Pr.

  In one embodiment, 70 mass% or more of R2 in the R2-Ga-Cu-Co-based alloy is Pr.

  In one embodiment, the total content of R 2 -Ga-Cu-Co in the R 2 -Ga-Cu-Co-based alloy is 80 mass% or more.

  In one embodiment, the temperature in the first heat treatment is 800 ° C. or more and 1000 ° C. or less.

  In one embodiment, the temperature in the second heat treatment is 480 ° C. or more and 560 ° C. or less.

Preparing the R1-T1-B based sintered body comprises performing after the material alloy particle size D ₅₀ was pulverized to 3μm or 10μm or less, the sintering being oriented in a magnetic field.

  The manufacturing method of the R-T-B-based sintered magnet of the present disclosure is, in another non-limiting exemplary embodiment, preparing an R1-T1-Cu-B-based sintered body; Preparing a Co-based alloy, contacting at least a part of the R2-Ga-Co-based alloy with at least a part of the surface of the R1-T1-Cu-B-based sintered body; A step of carrying out the first heat treatment at a temperature of 700 ° C. or more and 1100 ° C. or less in a gas atmosphere, and vacuum or failure for the R1-T1-Cu-B based sintered body for which the first heat treatment is carried out Carrying out the second heat treatment at a temperature of 450 ° C. to 600 ° C. in an active gas atmosphere, and in the R1-T1-Cu-B based sintered body, R1 is at least one of rare earth elements Yes, including at least one of Nd and Pr, The content of 1 is 27 mass% or more and 35 mass% or less of the entire R1-T1-Cu-B sintered body, and T1 is at least one selected from the group consisting of Fe, Co, Al, Mn, and Si. T1 always contains Fe, the content of Fe with respect to the whole T1 is 80 mass% or more, and the molar ratio of T1 to B ([T1] / [B]) is more than 14.0 and 15.0 or less The content of Cu is 0.1 mass% or more and 1.5 mass% or less of the entire R1-T1-Cu-B-based sintered body, and in the R2-Ga-Co-based alloy, R2 is a rare earth element. It is at least one type and necessarily contains at least one of Nd and Pr, and the content of R2 is 35 mass% or more and less than 87 mass% of the entire R2-Ga-Co alloy, and the content of Ga is R2-Ga. 2.5 mass% or more and 30 mass% or less of the whole Co alloy, the content of Co is more than 10 mass% and 45 mass% or less of the whole R2-Ga-Co alloy, the content of R2> the content of Co> An inequality of the content of Ga is established.

  In one embodiment, the molar ratio of T1 to B ([T1] / [B]) is 14.3 or more and 15.0 or less.

  In one embodiment, 50 mass% or more of R2 in the R2-Ga-Co-based alloy is Pr.

  In one embodiment, 70 mass% or more of R2 in the R2-Ga-Co-based alloy is Pr.

  In one embodiment, the total content of R2, Ga, and Co in the R2-Ga-Co-based alloy is 80 mass% or more.

  In one embodiment, the temperature in the first heat treatment is 800 ° C. or more and 1000 ° C. or less.

  In one embodiment, the temperature in the second heat treatment is 480 ° C. or more and 560 ° C. or less.

In certain embodiments, the step of preparing the R1-T1-Cu-B based sintered body, after the material alloy particle size D ₅₀ was pulverized to 3μm or 10μm or less, sintering is performed by orienting in a magnetic field Including.

According to embodiments of the present disclosure, while reducing the content of heavy rare earth elements, it is possible to provide a manufacturing method of the R-T-B based sintered magnet having a high B _r and a high H _cJ.

It is a flowchart which shows the example of the process in the manufacturing method (1st Embodiment) of the RTB-type sintered magnet by this indication. It is a schematic diagram which shows the main phase and grain boundary phase of a RTB type | system | group sintered magnet. It is the schematic diagram which further expanded the inside of the broken-line rectangular area | region of FIG. 2A. Arrangement of R1-T1-B based alloy sintered body (or R1-T1-Cu-B based sintered body) and R2-Ga-Cu-Co based alloy (or R2-Ga-Co based alloy) in heat treatment process It is explanatory drawing which shows a form typically. It is a flowchart which shows the example of the process in the manufacturing method (2nd Embodiment) of the RTB-type sintered magnet by this indication.

  In the present disclosure, rare earth elements may be collectively referred to as “R”. When referring to a specific element or group of elements among the rare earth elements R, for example, the sign of “R1” or “R2” is used to distinguish from other rare earth elements. Further, in the present disclosure, the entire transition metal element including Fe is denoted as “T”. When the transition metal element T includes both a specific element or element group and a specific element or element group other than the transition metal element which is easily substituted with the Fe site of the main phase, using the symbol of “T1” Distinguish from other transition metal elements.

First Embodiment
A method of manufacturing an RTB-based sintered magnet according to the first embodiment of the present disclosure includes, as shown in FIG. 1, a step S10 of preparing an R1-T1-B-based sintered body; And S20 of preparing a Cu-Co alloy. The order of the step S10 of preparing the R1-T1-B-based sintered body and the step S20 of preparing the R2-Ga-Cu-Co-based alloy is arbitrary, and each of the R1-T1-B is manufactured at different places. You may use B-type sintered compact and R2-Ga-Cu-Co-type alloy.

  In the present disclosure, RTB-based sintered magnets before and during the second heat treatment are referred to as R1-T1-B-based sintered bodies, and R1-T1-B-based magnets after the second heat treatment. The sintered body is simply referred to as an RTB-based sintered magnet.

In the R1-T1-B based sintered body, the following (A1) to (A3) hold.
(A1) R1 is at least one of rare earth elements and always contains at least one of Nd and Pr, and the content of R1 is 27 mass% or more and 35 mass% or less of the entire R1-T1-B sintered body.
(A2) T1 is at least one selected from the group consisting of Fe, Co, Al, Mn, and Si. T1 necessarily contains Fe, and the content of Fe with respect to the entire T1 is 80 mass% or more.
The molar ratio of T1 to (A3) B ([T1] / [B]) is more than 14.0 and 15.0 or less.

  The molar ratio of T1 to B ([T1] / [B]) in the present disclosure is the analysis value (mass%) of each element (Fe or at least one of Fe, Co, Al, Mn, Si and Fe) constituting T1. Calculate the ratio of the atomic weight of each element divided by the atomic weight of each element (a) and the ratio (a /) of the analytical value (mass%) of B divided by the atomic weight of B (b) b).

The fact that the molar ratio of T1 to B ([T1] / [B]) exceeds 14.0 means that the content ratio of B is lower than the stoichiometric composition ratio of the R ₂ T ₁₄ B compound. There is. In other words, the R1-T1-B based sintered body, relative B amount relative to the amount of T1 to be used in the formation of the main phase (R ₂ T ₁₄ B compound) is small.

The following (A4) to (A8) are established in the R2-Ga-Cu-Co based alloy.
(A4) R2 is at least one of rare earth elements and always contains at least one of Nd and Pr, and the content of R2 is 35 mass% or more and less than 85 mass% of the entire R2-Ga-Cu-Co alloy.
The content of (A5) Ga is 2.5 mass% or more and 30 mass% or less of the entire R2-Ga-Cu-Co alloy.
The content of (A6) Cu is 2.5 mass% or more and 20 mass% or less of the entire R2-Ga-Cu-Co alloy.
The content of (A7) Co is more than 10% by mass and 45% by mass or less of the whole of the R2-Ga-Cu-Co based alloy.
(A8) Content of R2> Content of Co> Content of Ga> Inequalities of Content of Cu are satisfied.

In the method of producing an RTB-based sintered magnet according to the present disclosure, R1 having a relatively small amount of B in a stoichiometric ratio with respect to the amount of T used for forming the main phase (R ₂ T ₁₄ B compound) The R2-Ga-Cu-Co alloy is brought into contact with at least a part of the surface of the T1-B sintered body, and as shown in FIG. 1, in a vacuum or inert gas atmosphere, at 700.degree. C. or more and 1100.degree. Temperature of 450 ° C. or more and 600 ° C. or less in a vacuum or inert gas atmosphere with respect to the step S30 of performing the first heat treatment at a temperature and the R1-T1-B based sintered body in which the first heat treatment is performed In step S40, the second heat treatment is performed. Thus, it is possible to obtain the R-T-B based sintered magnet having a high B _r and a high H _cJ.

  Another step, such as a cooling step, may be performed between the step S30 of performing the first heat treatment and the step S40 of performing the second heat treatment.

  First, the basic structure of the RTB-based sintered magnet will be described.

The R-T-B sintered magnet has a structure in which powder particles of a raw material alloy are bonded by sintering, and a main phase mainly composed of an R ₂ T ₁₄ B compound and a grain boundary portion of this main phase It is composed of the located grain boundary phase.

FIG. 2A is a schematic view showing the main phase and the grain boundary phase of the RTB-based sintered magnet, and FIG. 2B is a schematic view further enlarging the inside of the dashed rectangular area in FIG. 2A. In FIG. 2A, an arrow of 5 μm in length as an example is described for reference as a reference length indicating the size. As shown in FIGS. 2A and 2B, the RTB-based sintered magnet includes a main phase 12 mainly composed of an R ₂ T ₁₄ B compound, and a grain boundary phase 14 located in the grain boundary portion of the main phase 12. And consists of In addition, as shown in FIG. 2B, the grain boundary phase 14 is a two-grain grain boundary phase 14a in which two R ₂ T ₁₄ B compound particles (grains) are adjacent, and three or more R ₂ T ₁₄ B compound particles. And the adjacent grain boundary triple point 14b.

The R ₂ T ₁₄ B compound which is the main phase 12 is a ferromagnetic phase having high saturation magnetization and anisotropic magnetic field. Therefore, in the R-T-B based sintered magnet, it is possible to improve the B _r by increasing the existence ratio of R ₂ T ₁₄ B compound is the main phase 12. In order to increase the abundance ratio of the R ₂ T ₁₄ B compound, the R amount, T amount, B amount in the raw material alloy and the stoichiometric ratio of the R ₂ T ₁₄ B compound (R amount: T amount: B amount = It should be close to 2: 14: 1). When the amount of B or R for forming the R ₂ T ₁₄ B compound is less than the stoichiometric ratio, generally, a ferromagnetic substance such as an Fe phase or an R ₂ T ₁₇ phase is formed in the grain boundary phase 14 , H _cJ falls sharply. However, as in the method described in Patent Document 1, the amount of B is less than the stoichiometric ratio of the R ₂ T ₁₄ B compound, and at least one selected from Al, Ga, and Cu. the inclusion of the metal element M, it is possible to obtain a high H _cJ in the grain boundary to the transition metal-rich phase from the R ₂ T ₁₇ phase (e.g. R-T-Ga phase) is generated. However, in the method described in Patent Document 1, _Br is significantly reduced.

As a result of investigations, the present inventors have found that R2-Ga-Cu- containing a relatively large amount of Co on at least a part of the surface of the R1-T1-B based sintered body having a specific composition having a low B composition. When contacting the Co-based alloy that perform particular heat treatment, surprisingly, finally sintered magnet obtained has been found to be achieved a high B _r and high H _cJ.

The manufacturing method of the RTB-based sintered magnet according to the present disclosure is such that R2, Ga, Cu and Co are introduced into the interior from the magnet surface by the R2-Ga-Cu-Co-based alloy having the specific composition of the present disclosure. , it is possible to achieve high B _r and high H _cJ.

(Step of preparing R1-T1-B sintered body)
First, the composition of the sintered body in the step of preparing an R1-T1-B-based sintered body (hereinafter sometimes simply referred to as "sintered body") will be described.

R1 is at least one of rare earth elements and always contains at least one of Nd and Pr. In order to improve _HcJ of the R1-T1-B-based sintered body, a small amount of heavy rare earth elements such as Dy, Tb, Gd, and Ho generally used may be included. However, according to the manufacturing method according to the present disclosure, sufficiently high _HcJ can be obtained without using a large amount of heavy rare earth elements. Therefore, the content of the heavy rare earth element is preferably 1 mass% or less of the R1-T1-B sintered body, more preferably 0.5 mass% or less, and not contained (substantially 0 mass%) Is more preferred.

  The content of R1 is 27 mass% or more and 35 mass% or less of the entire R1-T1-B sintered body. If the content of R1 is less than 27 mass%, a liquid phase is not sufficiently generated in the sintering process, and it becomes difficult to fully densify the R1-T1-B-based sintered body. On the other hand, although the effect of the present disclosure can be obtained even if the content of R1 exceeds 35 mass%, the alloy powder in the manufacturing process of the R1-T1-B-based sintered body becomes very active. As a result, significant oxidation or ignition of the alloy powder may occur, so 35 mass% or less is preferable. The content of R1 is more preferably 27.5 mass% or more and 33 mass% or less, and still more preferably 28 mass% or more and 32 mass% or less.

T1 is at least one selected from the group consisting of Fe, Co, Al, Mn, and Si, and T1 always contains Fe. That is, T1 may be Fe alone, or may be Fe and at least one of Co, Al, Mn, and Si. However, the content of Fe with respect to the whole T1 is 80 mass% or more. When the content of Fe is less than 80 mass%, B _r and H _cJ may be reduced. Here, "the content of Fe with respect to the whole T1 is 80 mass% or more" means, for example, when the content of T1 in the R1-T1-B-based sintered body is 70 mass%, R1-T1-B-based sintering It says that 56 mass% or more of the body is Fe. Preferably, the content of Fe with respect to the whole of T1 is 90 mass% or more. This is because it is possible to obtain a higher B _r and a high H _cJ. The preferable content in the case of containing Co, Al, Mn, and Si is 5.0 mass% or less of Co, 1.5 mass% or less of Al, and Mn and Si in the entire R1-T1-Cu-B sintered body. Each is 0.2 mass% or less.

  The molar ratio of T1 to B ([T1] / [B]) is more than 14.0 and 15.0 or less.

  The molar ratio of T1 to B ([T1] / [B]) in the present disclosure is the analysis value (mass%) of each element (Fe or at least one of Fe, Co, Al, Mn, Si and Fe) constituting T1. Calculate the ratio of the atomic weight of each element divided by the atomic weight of each element (a) and the ratio (a /) of the analytical value (mass%) of B divided by the atomic weight of B (b) b).

The condition that the molar ratio of T1 to B ([T1] / [B]) exceeds 14.0 means that the amount of B is relatively to the amount of T1 used to form the main phase (R ₂ T ₁₄ B compound) It shows that there are few. If the molar ratio of T1 to B ([T1] / [B]) is 14.0 or less, high H _cJ can not be obtained. On the other hand, mol ratio of T1 for B ([T1] / [B ]) is likely to decrease B _r exceeds 15.0. The molar ratio of T1 to B ([T1] / [B]) is preferably 14.5 or more and 15.0 or less. It is possible to obtain a higher B _r and a high H _cJ. Further, the content of B is preferably 0.9 mass% or more and less than 1.0 mass% of the entire R1-T1-B sintered body.

In addition to the above elements, the R1-T1-B based sintered body may be made of Ga, Cu, Ag, Zn, In, Sn, Zr, Nb, Ti, Ni, Hf, Ta, W, Ge, Mo, V, Y, La, Ce, Sm, Ca, Mg, Cr, H, F, P, S, Cl, O, N, C and the like may be contained. The content of each of Ga, Cu, Ag, Zn, In, Sn, Zr, Nb and Ti is 0.5 mass% or less, Ni, Hf, Ta, W, Ge, Mo, V, Y, La, Ce, It is preferable that Sm, Ca, Mg and Cr each be 0.2 mass% or less, H, F, P, S and Cl be 500 ppm or less, O be 6000 ppm or less, N be 1000 ppm or less and C be 1500 ppm or less. The total content of these elements is preferably 5% by mass or less of the entire R1-T1-B-based sintered body. The total content of these elements may not be able to obtain the high B _r and high H _cJ exceeds 5 mass% of the total R1-T1-B based sintered body.

Next, the process of preparing an R1-T1-B sintered body will be described. The step of preparing the R1-T1-B based sintered body can be prepared using a general manufacturing method represented by the RTB based sintered magnet. The R1-T1-B sintered body is crushed in a magnetic field after the raw material alloy is pulverized to a particle size D ₅₀ (volume center value D ₅₀ obtained by measurement by air flow dispersion laser diffraction method) of 3 μm to 10 μm. It is preferable to perform orientation and sintering. As an example, a material alloy that has been prepared in such a strip casting method, after the particle size D ₅₀ by using a jet mill is ground to 3μm over 10μm or less, and molded in a magnetic field, 900 ° C. or higher 1100 ° C. or less It can be prepared by sintering at a temperature of The size less than D ₅₀ of the material alloy is 3μm is very difficult to prepare a pulverized powder is not preferable because production efficiency is greatly reduced. Meanwhile, undesirably particle diameter D ₅₀ is eventually only the crystal grain size of the resulting R1-T1-B based sintered body increases exceeds 10 [mu] m, it becomes difficult to obtain a high H _cJ. The particle size D ₅₀ is preferably 3 μm or more and 5 μm or less.

  The R1-T1-B based sintered body may be produced from one kind of raw material alloy (single raw material alloy) as long as the above-mentioned respective conditions are satisfied, or two or more kinds of raw material alloys may be used to produce them. It may be produced by the method of mixing (blending method). The obtained R1-T1-B-based sintered body may be subjected to known mechanical processing such as cutting and cutting, if necessary, and may then be subjected to the first heat treatment and the second heat treatment described later. .

(Step of preparing R2-Ga-Cu-Co alloy)
First, the composition of the R2-Ga-Cu-Co alloy in the step of preparing the R2-Ga-Cu-Co alloy will be described. By including all of R, Ga, Cu, and Co within the specific range described below, R2, Ga, Cu, and R2 in the R2-Ga-Cu-Co alloy in the step of performing the first heat treatment described later Co can be introduced into the interior of the R1-T1-B sintered body.

R2 is at least one of rare earth elements and always contains at least one of Nd and Pr. It is preferable that 50 mass% or more of R2 is Pr. It is because higher H _cJ can be obtained. Here, "50 mass% or more of R2 is Pr" means, for example, 25 mass of R2-Ga-Cu-Co alloy when the content of R2 in R2-Ga-Cu-Co alloy is 50 mass%. It says that% or more is Pr. More preferably, 70 mass% or more of R2 is Pr, and most preferably, R2 is only Pr (including unavoidable impurities). Thereby, a further higher _HcJ can be obtained. In addition, a small amount of heavy rare earth elements such as Dy, Tb, Gd and Ho may be contained as R2. However, according to the manufacturing method of the present disclosure, sufficiently high _HcJ can be obtained without using a large amount of heavy rare earth elements. Therefore, the content of the heavy rare earth element is preferably 10 mass% or less of the entire R2-Ga-Cu-Co alloy (the heavy rare earth element in the R2-Ga-Cu-Co alloy is 10 mass% or less), It is more preferable that it is 5 mass% or less, and it is still more preferable that it does not contain (substantially 0 mass%). Even when R2 of the R2-Ga-Cu-Co alloy contains a heavy rare earth element, it is preferable that 50% or more of R2 is Pr, and only R2 excluding heavy rare earth elements is Pr (including unavoidable impurities) It is more preferred that

The content of R2 is 35 mass% or more and less than 85 mass% of the entire R2-Ga-Cu-Co alloy. If the content of R2 is less than 35 mass%, diffusion may not sufficiently proceed in the first heat treatment described later. On the other hand, although the effect of the present disclosure can be obtained even if the content of R2 is 85 mass% or more, the alloy powder in the manufacturing process of the R2-Ga-Cu-Co based alloy becomes very active. As a result, significant oxidation, ignition and the like of the alloy powder may occur, so the content of R2 is preferably less than 85 mass% of the entire R2-Ga-Cu-Co alloy. The content of R2 is more preferably 50 mass% or more and less than 85 mass%, and still more preferably 60 mass% or more and less than 85 mass%. It is because higher H _cJ can be obtained.

Ga is 2.5 mass% or more and 30 mass% or less of the entire R2-Ga-Cu-Co alloy. If Ga is less than 2.5 mass%, it is difficult to introduce Co in the R2-Ga-Cu-Co alloy into the inside of the R1-T1-B sintered body in the step of performing the first heat treatment described later, which is high. I can not get B _r . Furthermore, the generation amount of the R-T-Ga phase is too small to obtain high _HcJ . On the other hand, if Ga is more than 30 mass%, B _r may be lowered significantly. Ga is more preferably 4 mass% or more and 20 mass% or less, and still more preferably 4 mass% or more and 10 mass% or less. This is because it is possible to obtain a higher B _r and a high H _cJ.

Cu is 2.5 mass% or more and 20 mass% or less of the entire R2-Ga-Cu-Co alloy. If Cu is less than 2.5 mass%, Ga, Cu and Co in the R2-Ga-Cu-Co alloy are introduced into the interior of the R1-T1-B sintered body in the step of performing the first heat treatment described later hardly be, it is impossible to obtain a high B _r. On the other hand, when Cu exceeds 20 mass%, the abundance ratio of Ga at the grain boundaries decreases, so the amount of R-T-Ga phase formed may be too small to obtain high _HcJ . Cu is more preferably 4 mass% or more and 15 mass% or less, and still more preferably 4 mass% or more and 10 mass% or less. This is because it is possible to obtain a higher B _r and a high H _cJ.

Co is more than 10 mass% and 45 mass% or less of the entire R2-Ga-Cu-Co alloy. Co is in the following 10 mass%, it is impossible to sufficiently enhance the finally obtained R-T-B based sintered magnet of B _r. On the other hand, when Co exceeds 45Mass%, it may not be able to spread with a first heat treatment to be described later does not proceed sufficiently to obtain a high B _r and high H _cJ. As for Co, it is more preferable that they are 15 mass% or more and 30 mass% or less. This is because it is possible to obtain a higher B _r and a high H _cJ.

Further, in the R2-Ga-Cu-Co-based alloy in the present disclosure, an inequality expression of R2 content> Co content> Ga content> Cu content is satisfied. Therefore, it is possible to obtain a high B _r and a high H _cJ. It is considered that this is because a phase containing appropriate amounts of R, Co, Ga and Cu is generated at two grain boundaries by satisfying the inequality of the present disclosure.

  In addition to the above elements, the R2-Ga-Cu-Co alloy may contain Al, Ag, Zn, Si, In, Sn, Zr, Nb, Ti, Ni, Hf, Ta, W, Ge, Mo, V, Y, La, Ce, Sm, Ca, Mg, Mn, Cr, H, F, P, S, Cl, O, N, C and the like may be contained.

The content of Al is 1.0 mass% or less, Ag, Zn, Si, In, Sn, Zr, Nb, and Ti are 0.5 mass% or less, respectively, Ni, Hf, Ta, W, Ge, Mo, V, Y, La, Ce, Sm, Ca, Mg, Mn, Si, Cr each 0.2 mass% or less, H, F, P, S, Cl 500 ppm or less, O 6000 ppm or less, N 1000 ppm or less, C 1500 ppm or less is preferable. However, the total content of these elements is more than 20mass%, R2-Ga-Cu -Co -based then the amount of R2-Ga-Cu-Co in the alloy, to obtain a high B _r and high H _cJ It may not be possible. Therefore, 80 mass% or more is preferable and, as for content of the sum total of R2-Ga-Cu-Co in R2-Ga-Cu-Co type alloy, 90 mass% or more is still more preferable.

  Next, the process of preparing an R2-Ga-Cu-Co based alloy will be described. The R2-Ga-Cu-Co alloy is a method of producing a raw material alloy employed in a general manufacturing method represented by a Nd-Fe-B sintered magnet, for example, a die casting method and a strip casting method And single roll ultra-quenching method (melt spinning method) or atomization method. In addition, the R2-Ga-Cu-Co based alloy may be one obtained by pulverizing the alloy obtained as described above by a known pulverizing means such as a pin mill. Further, in order to improve the grindability of the alloy obtained as described above, heat treatment at 700 ° C. or less in a hydrogen atmosphere may be performed to contain hydrogen and then grinding.

(Step of carrying out the first heat treatment)
At least a part of the R2-Ga-Cu-Co alloy is brought into contact with at least a part of the surface of the R1-T1-B sintered body prepared as described above, and the temperature is 700 ° C. or higher in a vacuum or inert gas atmosphere. Heat treatment is performed at a temperature of 1100 ° C. or less. In the present disclosure, this heat treatment is referred to as a first heat treatment. Thereby, a liquid phase containing Cu, Ga and Co is generated from the R2-Ga-Cu-Co alloy, and the liquid phase passes through the grain boundaries of the R1-T1-B sintered body, and the surface of the sintered body is produced. It is diffused from inside to inside. When the first heat treatment temperature is lower than 700 ° C., Cu, and amount of liquid phase containing Ga and Co is too small, it may not be able to obtain a high B _r and high H _cJ. On the other hand, when the temperature exceeds 1100 ° C., abnormal grain growth of the main phase occurs and H _cJ may decrease. The first heat treatment temperature is preferably 800 ° C. or more and 1000 ° C. or less. This is because it is possible to obtain a higher B _r and a high H _cJ. The heat treatment time is set to an appropriate value depending on the composition and dimensions of the R1-T1-B-based sintered body and R2-Ga-Cu-Co-based alloy, the heat treatment temperature, etc., preferably 5 minutes to 20 hours or less. More preferably, minutes to 15 hours and still more preferably 30 minutes to 10 hours. Moreover, it is preferable to prepare 2 mass% or more and 30 mass% or less of R2-Ga-Cu-Co type alloy with respect to the weight of R1-T1-B type sintered compact. If the amount of the R2-Ga-Cu-Co alloy is less than 2 mass% with respect to the weight of the R1-T1-B sintered body, there is a possibility that _HcJ may decrease. On the other hand, there is a possibility that the B _r decreases exceeds 30 mass%.

  The first heat treatment can be performed by disposing an R2-Ga-Cu-Co alloy having an arbitrary shape on the surface of the R1-T1-B sintered body and using a known heat treatment apparatus. For example, the first heat treatment can be performed by covering the surface of the R1-T1-B-based sintered body with a powder layer of an R2-Ga-Cu-Co-based alloy. For example, after a slurry in which an R2-Ga-Cu-Co alloy is dispersed in a dispersion medium is applied to the surface of an R1-T1-B sintered body, the dispersion medium is evaporated to form an R2-Ga-Cu-Co system. The alloy and the R1-T1-B sintered body may be in contact with each other. In addition, as shown in the experimental examples described later, the R2-Ga-Cu-Co based alloy may be arranged to be in contact with the surface perpendicular to the orientation direction of at least the R1-T1-B based sintered body. preferable. In addition, alcohol (ethanol etc.), NMP (N-methyl pyrrolidone), an aldehyde, and a ketone can be illustrated as a dispersion medium. Moreover, you may perform well-known mechanical processing, such as a cutting | disconnection and cutting, with respect to R1-T1-B type | system | group sintered compact in which 1st heat processing was implemented.

(Step of carrying out the second heat treatment)
The R1-T1-B-based sintered body subjected to the first heat treatment is heat-treated at a temperature of 450 ° C. or more and 600 ° C. or less in a vacuum or an inert gas atmosphere. In the present disclosure, this heat treatment is referred to as a second heat treatment. By performing the second heat treatment, it is possible to obtain a high B _r and high H _cJ. When the temperature of the second heat treatment is less than 450 ° C. and more than 600 ° C., the amount of R-T-Ga phase (typically, R ₆ T ₁₃ Z phase (Z is at least one of Cu and Ga)) There is a possibility that high B _r and high H _cJ can not be obtained due to too little. The second heat treatment temperature is preferably 480 ° C. or more and 560 ° C. or less. Higher H _cJ can be obtained. The heat treatment time is set to an appropriate value according to the composition and dimensions of the R1-T1-B sintered body, the heat treatment temperature, etc., preferably 5 minutes to 20 hours, more preferably 10 minutes to 15 hours, and 30 More preferably, minutes to 10 hours.

In the above R ₆ T ₁₃ Z phase (R ₆ T ₁₃ Z compound), R is at least one rare earth element and necessarily includes at least one of Pr and Nd, and T is at least one transition metal element. Yes Fe must be included. The R ₆ T ₁₃ Z compound is typically an Nd ₆ Fe ₁₃ Ga compound. Further, the R ₆ T ₁₃ Z compound has a La ₆ Co ₁₁ Ga ₃ type crystal structure. The R ₆ T ₁₃ Z compound may be an R ₆ T _{13 −} δZ ₁₊ δ compound depending on the state. When relatively large amounts of Cu, Al, and Si are contained in the RTB-based sintered magnet, R ₆ T _13- δ (Ga _{1 -abc} Cu _a Al _b Si _c ) 1 ₊ δ It may have been.

  The R-T-B-based sintered magnet obtained by the step of performing the second heat treatment described above is subjected to known surface treatment such as plating for imparting corrosion resistance or performing known machining such as cutting or cutting. It can be performed. In addition, the RTB-based sintered magnet obtained by the production method of the present disclosure is characterized in that at least one of Fe or Co, Al, Mn, Si and Fe in the RTB-based sintered magnet and T2 ( The molar ratio of T2 to B ([T2] / [B]) is more than 14.0, and R, Fe, B, Cu, Ga Contains In addition to R, Fe, B, Cu, Ga, Co, Al, Ag, In, Sn, Zr, Nb, Ti, Ni, Hf, Ta, W, Ge, Mo, V, Y, La, Ce, Sm, Ca, Mg, Mn, Si, Cr, H, F, P, S, Cl, O, N, C and the like may be contained.

Second Embodiment
Next, a method of manufacturing the RTB-based sintered magnet according to the second embodiment of the present disclosure will be described.

  As shown in FIG. 4, the method of manufacturing the RTB-based sintered magnet according to the second embodiment of the present disclosure includes a step S110 of preparing an R1-T1-Cu-B-based sintered body; And S120 of preparing a Ga-Co based alloy. The order of the step S110 of preparing the R1-T1-Cu-B-based sintered body and the step S120 of preparing the R2-Ga-Co-based alloy is arbitrary, and each of the R1-T1-made in different places is manufactured. A Cu-B based sintered body and an R2-Ga-Co based alloy may be used.

In the R1-T1-Cu-B based sintered body, the following (B1) to (B4) hold.
(B1) R1 is at least one of rare earth elements and always contains at least one of Nd and Pr, and the content of R1 is 27 mass% or more and 35 mass% or less of the entire R1-T1-Cu-B sintered body .
(B2) T1 is at least one selected from the group consisting of Fe, Co, Al, Mn, and Si. T1 necessarily contains Fe, and the content of Fe with respect to the entire T1 is 80 mass% or more.
(B3) The molar ratio of T1 to B ([T1] / [B]) is more than 14.0 and 15.0 or less.
The content of (B4) Cu is 0.1 mass% or more and 1.5 mass% or less of the entire R1-T1-Cu-B-based sintered body.

  The molar ratio of T1 to B ([T1] / [B]) in the present disclosure is the analysis value (mass%) of each element (Fe or at least one of Fe, Co, Al, Mn, Si and Fe) constituting T1. Calculate the ratio of the atomic weight of each element divided by the atomic weight of each element (a) and the ratio (a /) of the analytical value (mass%) of B divided by the atomic weight of B (b) b).

The fact that the molar ratio of T1 to B ([T1] / [B]) exceeds 14.0 means that the content ratio of B is lower than the stoichiometric composition ratio of the R ₂ T ₁₄ B compound. There is. In other words, the R1-T1-Cu-B-based sintered body, relative B amount relative to the amount of T1 to be used in the formation of the main phase (R ₂ T ₁₄ B compound) is small.

In the R2-Ga-Co based alloy, the following (B5) to (B8) hold.
(B5) R2 is at least one of rare earth elements and necessarily contains at least one of Nd and Pr, and the content of R2 is 35 mass% or more and less than 87 mass% of the entire R2-Ga-Co alloy.
The content of (B6) Ga is 2.5 mass% or more and 30 mass% or less of the entire R2-Ga-Co alloy.
The content of (B7) Co is more than 10% by mass and 45% by mass or less of the entire R2-Ga-Co-based alloy.
(B8) R2 content> Co content> Ga content inequality holds.

In the method of producing an RTB-based sintered magnet according to the present disclosure (the second embodiment), the relative stoichiometric ratio to the amount of T used to form the main phase (R ₂ T ₁₄ B compound) The R2-Ga-Co alloy is brought into contact with at least a part of the surface of the R1-T1-Cu-B-based sintered body having a small amount of B, as shown in FIG. 4, in a vacuum or inert gas atmosphere, Step S130 of performing the first heat treatment at a temperature of 700 ° C. or more and 1100 ° C. or less, and in a vacuum or inert gas atmosphere with respect to the R1-T1-Cu-B-based sintered body in which the first heat treatment is performed Step S140 of performing the second heat treatment at a temperature of 450 ° C. or more and 600 ° C. or less is performed. Thus, it is possible to obtain the R-T-B based sintered magnet having a high B _r and a high H _cJ.

  Another step, such as a cooling step, may be performed between step S130 of performing the first heat treatment and step S140 of performing the second heat treatment.

As a result of investigations, the present inventors found that R2-Ga-Co having a relatively high Co content in at least a part of the surface of the R1-T1-Cu-B-based sintered body having a specific composition having a low B composition. even if after specific heat treatment by contacting the system alloy, finally sintered magnet obtained has been found to be achieved a high B _r and high H _cJ.

The method for producing an RTB-based sintered magnet according to the present disclosure (the second embodiment) introduces R2, Ga, and Co into the interior from the magnet surface with the R2-Ga-Co-based alloy of the specific composition of the present disclosure. by, it is possible to realize a high B _r and high H _cJ.

(Step of preparing R1-T1-Cu-B-based sintered body)
First, the composition of the sintered body in the step of preparing an R1-T1-Cu-B-based sintered body will be described.

R1 is at least one of rare earth elements and always contains at least one of Nd and Pr. In order to improve _HcJ of the R1-T1-Cu-B-based sintered body, a small amount of heavy rare earth elements such as Dy, Tb, Gd, and Ho generally used may be contained. However, according to the manufacturing method according to the present disclosure, sufficiently high _HcJ can be obtained without using a large amount of heavy rare earth elements. Therefore, the content of the heavy rare earth element is preferably 1 mass% or less of the R1-T1-Cu-B-based sintered body, more preferably 0.5 mass% or less, and it is not contained (substantially) More preferably, 0 mass%).

  The content of R1 is 27 mass% or more and 35 mass% or less of the entire R1-T1-Cu-B-based sintered body. If the content of R1 is less than 27 mass%, a liquid phase is not sufficiently generated in the sintering process, and it becomes difficult to fully densify the R1-T1-Cu-B-based sintered body. On the other hand, although the effect of the present disclosure can be obtained even if the content of R1 exceeds 35 mass%, the alloy powder in the manufacturing process of the R1-T1-Cu-B-based sintered body becomes very active. As a result, significant oxidation or ignition of the alloy powder may occur, so 35 mass% or less is preferable. The content of R1 is more preferably 27.5 mass% or more and 33 mass% or less, and still more preferably 28 mass% or more and 32 mass% or less.

T1 is at least one selected from the group consisting of Fe, Co, Al, Mn, and Si, and T1 always contains Fe. That is, T1 may be Fe alone, or may be Fe and at least one of Co, Al, Mn, and Si. However, the content of Fe with respect to the whole T1 is 80 mass% or more. When the content of Fe is less than 80 mass%, B _r and H _cJ may be reduced. Here, "the content of Fe with respect to the whole T1 is 80 mass% or more" means, for example, R1-T1-Cu- when the content of T1 in the R1-T1-Cu-B-based sintered body is 70 mass%. It says that 56 mass% or more of B-type sintered compact is Fe. Preferably, the content of Fe with respect to the whole of T1 is 90 mass% or more. This is because it is possible to obtain a higher B _r and a high H _cJ. The preferable content in the case of containing Co, Al, Mn, and Si is 5.0 mass% or less of Co, 1.5 mass% or less of Al, and Mn and Si in the entire R1-T1-Cu-B sintered body. Each is 0.2 mass% or less.

  The molar ratio of T1 to B ([T1] / [B]) is more than 14.0 and 15.0 or less.

  As described above, the molar ratio of T1 to B ([T1] / [B]) in the present disclosure is an analysis of each element (Fe or at least one of Co, Al, Mn, Si, and Fe) constituting T1. The value (mass%) divided by the atomic weight of each element is determined, and the sum of the values (a) and the analytical value of B (mass%) divided by the atomic weight of B (b) Ratio (a / b).

The condition that the molar ratio of T1 to B ([T1] / [B]) exceeds 14.0 means that the amount of B is relatively to the amount of T1 used to form the main phase (R ₂ T ₁₄ B compound) It shows that there are few. If [T1] / [B] is 14.0 or less, high H _cJ can not be obtained. On the other hand, there is a possibility to lower the B _r exceeds the 15.0 [T1] / [B] . [T1] / [B] is preferably 14.3 or more and 15.0 or less. It is possible to obtain a higher B _r and a high H _cJ. In addition, the content of B is preferably 0.9 mass% or more and less than 1.0 mass% of the entire R1-T1-Cu-B-based sintered body.

The content of Cu is 0.1 mass% or more and 1.5 mass% or less of the entire R1-T1-Cu-B-based sintered body. If Cu is less than 0.1 mass%, diffusion may not sufficiently proceed in the first heat treatment described later, and high H _cJ may not be obtained. On the other hand, Cu is the exceeding 1.5 mass% B _r may be reduced.

Also in the present embodiment, the R1-T1-Cu-B-based sintered body contains Ga, Ag, Zn, In, Sn, Zr, Nb, Ti, Ni, Hf, Ta, W, Ge, in addition to the above elements. Mo, V, Y, La, Ce, Sm, Ca, Mg, Cr, H, F, P, S, Cl, O, N, C and the like may be contained. The content of each of Ga, Ag, Zn, In, Sn, Zr, Nb and Ti is 0.5 mass% or less, Ni, Hf, Ta, W, Ge, Mo, V, Y, La, Ce, Sm, It is preferable that Ca, Mg and Cr each be 0.2 mass% or less, H, F, P, S and Cl be 500 ppm or less, O be 6000 ppm or less, N be 1000 ppm or less and C be 1500 ppm or less. The total content of these elements is preferably 5 mass% or less of the entire R1-T1-Cu-B-based sintered body. The total content of these elements may not be able to obtain more than the high B _r and high H _cJ of 5 mass% of the total R1-T1-Cu-B-based sintered body.

Next, the process of preparing an R1-T1-Cu-B-based sintered body will be described. The step of preparing the R1-T1-Cu-B-based sintered body can be prepared using a general manufacturing method represented by an RTB-based sintered magnet. The R1-T1-Cu-B-based sintered body is a magnetic field after the raw material alloy is pulverized to a particle size D ₅₀ (volume center value obtained by measurement by air flow distribution laser diffraction = D ₅₀ ) of 3 μm to 10 μm. It is preferable to carry out sintering by orientating in the inside. As an example, a material alloy that has been prepared in such a strip casting method, after the particle size D ₅₀ by using a jet mill is ground to 3μm over 10μm or less, and molded in a magnetic field, 900 ° C. or higher 1100 ° C. or less It can be prepared by sintering at a temperature of The size less than D ₅₀ of the material alloy is 3μm is very difficult to prepare a pulverized powder is not preferable because production efficiency is greatly reduced. Meanwhile, undesirably particle diameter D ₅₀ is eventually only the crystal grain size of the R1-T1-Cu-B based sintered body obtained becomes large exceeding 10 [mu] m, it becomes difficult to obtain a high H _cJ. The particle size D ₅₀ is preferably 3 μm or more and 5 μm or less.

  The R1-T1-Cu-B sintered body may be produced from one kind of raw material alloy (single raw material alloy) as long as the above-mentioned respective conditions are satisfied, and two or more kinds of raw material alloys are used. It may be produced by a method of mixing them (blending method). The obtained R1-T1-Cu-B-based sintered body is subjected to known machining such as cutting and cutting as necessary, and is then subjected to the first heat treatment and the second heat treatment described later. It is also good.

(Step of preparing R2-Ga-Co based alloy)
First, the composition of the R2-Ga-Co-based alloy in the step of preparing the R2-Ga-Co-based alloy will be described. By including all of R, Ga, and Co in the specific range described below, in the step of performing the first heat treatment described later, R1, Ga, and Co in the R2-Ga-Co alloy are R1-T1- It can be introduced into the inside of a Cu-B-based sintered body.

R2 is at least one of rare earth elements and always contains at least one of Nd and Pr. It is preferable that 50 mass% or more of R2 is Pr. It is because higher H _cJ can be obtained. Here, “50 mass% or more of R2 is Pr” means that, for example, when the content of R2 in the R2-Ga-Co alloy is 50 mass%, 25 mass% or more of the R2-Ga-Co alloy is Pr Say that. More preferably, 70 mass% or more of R2 is Pr, and most preferably, R2 is only Pr (including unavoidable impurities). Thereby, a further higher _HcJ can be obtained. In addition, a small amount of heavy rare earth elements such as Dy, Tb, Gd and Ho may be contained as R2. However, according to the manufacturing method of the present disclosure, sufficiently high _HcJ can be obtained without using a large amount of heavy rare earth elements. Therefore, the content of the heavy rare earth element is preferably 10 mass% or less of the entire R2-Ga-Co alloy (the heavy rare earth element in the R2-Ga-Co alloy is 10 mass% or less), and is 5 mass% or less Some are more preferable, and it is more preferable not to contain (substantially 0 mass%). Even when R2 of the R2-Ga-Co alloy contains a heavy rare earth element, it is preferable that 50% or more of R2 is Pr, and R2 excluding the heavy rare earth element is only Pr (including unavoidable impurities) It is more preferable that

The content of R2 is 35 mass% or more and less than 87 mass% of the entire R2-Ga-Co alloy. If the content of R2 is less than 35 mass%, diffusion may not sufficiently proceed in the first heat treatment described later. On the other hand, although the effect of the present disclosure can be obtained even if the content of R2 is 87 mass% or more, the alloy powder in the manufacturing process of the R2-Ga-Co-based alloy becomes very active. As a result, significant oxidation, ignition and the like of the alloy powder may occur, so the content of R2 is preferably less than 85 mass% of the entire R2-Ga-Co based alloy. The content of R2 is more preferably 50 mass% or more and less than 85 mass%, and still more preferably 60 mass% or more and less than 85 mass%. It is because higher H _cJ can be obtained.

Ga is 2.5 mass% or more and 30 mass% or less of the entire R2-Ga-Co alloy. If Ga is less than 2.5 mass%, it is difficult to introduce Co in the R2-Ga-Co-based alloy into the interior of the R1-T1-Cu-B-based sintered body in the step of performing the first heat treatment described later, which is high I can not get B _r . Furthermore, the generation amount of the R-T-Ga phase is too small to obtain high _HcJ . On the other hand, if Ga is more than 30 mass%, B _r may be lowered significantly. Ga is more preferably 4 mass% or more and 20 mass% or less, and still more preferably 4 mass% or more and 10 mass% or less. This is because it is possible to obtain a higher B _r and a high H _cJ.

Co is more than 10 mass% and 45 mass% or less of the entire R2-Ga-Co alloy. Co is in the following 10 mass%, it is impossible to sufficiently enhance the finally obtained R-T-B based sintered magnet of B _r. On the other hand, when Co exceeds 45Mass%, it may not be able to spread with a first heat treatment to be described later does not proceed sufficiently to obtain a high B _r and high H _cJ. As for Co, it is more preferable that they are 15 mass% or more and 30 mass% or less. This is because it is possible to obtain a higher B _r and a high H _cJ.

Moreover, in the R2-Ga-Cu-Co based alloy in the present disclosure, the inequality of the content of R2> the content of Co> the content of Ga is satisfied. Therefore, it is possible to obtain a high B _r and a high H _cJ. It is considered that this is because a phase containing appropriate amounts of R, Co and Ga is generated at two grain boundaries by satisfying the inequality of the present disclosure.

  In addition to the above-mentioned elements, the R2-Ga-Co alloy contains Cu, Al, Ag, Zn, Si, In, Sn, Zr, Nb, Ti, Ni, Hf, Ta, W, Ge, Mo, V, Y, La, Ce, Sm, Ca, Mg, Mn, Cr, H, F, P, S, Cl, O, N, C and the like may be contained.

The content of Cu, Al is 1.0 mass% or less, Ag, Zn, Si, In, Sn, Zr, Nb, and Ti is 0.5 mass% or less, respectively, Ni, Hf, Ta, W, Ge, Mo, V, Y, La, Ce, Sm, Ca, Mg, Mn, Si, Cr each 0.2 mass% or less, H, F, P, S, Cl 500 ppm or less, O 6000 ppm or less, N 1000 ppm or less, As for C, 1500 ppm or less is preferable. However, when the total content of these elements exceeds 20mass%, R2-Ga-Co-based R2 in the alloy, Ga, then the amount of Co, can not be obtained a high B _r and high H _cJ There is sex. Therefore, 80 mass% or more is preferable and, as for content of the sum total of R2, Ga, and Co in R2-Ga-Co type alloy, 90 mass% or more is still more preferable.

  Next, the process of preparing an R2-Ga-Co based alloy will be described. The R2-Ga-Co based alloy is a method of producing a raw material alloy employed in a general production method represented by a Nd-Fe-B based sintered magnet, for example, a die casting method, a strip casting method or a single method. It can be prepared using a roll ultra-quenching method (melt spinning method) or an atomizing method. In addition, the R2-Ga-Co based alloy may be one obtained by pulverizing the alloy obtained as described above by a known pulverizing means such as a pin mill. Further, in order to improve the grindability of the alloy obtained as described above, heat treatment at 700 ° C. or less in a hydrogen atmosphere may be performed to contain hydrogen and then grinding.

(Step of carrying out the first heat treatment)
At least a portion of the R2-Ga-Co alloy is brought into contact with at least a portion of the surface of the R1-T1-Cu-B-based sintered body prepared as described above, and the temperature is 700 ° C. or higher in a vacuum or inert gas atmosphere. Heat treatment is performed at a temperature of 1100 ° C. or less. In the present disclosure, this heat treatment is referred to as a first heat treatment. As a result, a liquid phase containing Ga and Co is generated from the R2-Ga-Co alloy, and the liquid phase passes from the surface of the sintered body via the grain boundaries of the R1-T1-Cu-B sintered body. Diffusion is introduced. When the first heat treatment temperature is lower than 700 ° C., and too small amount of liquid phase containing Ga and Co, there is a possibility that it is impossible to obtain a high B _r and high H _cJ. On the other hand, when the temperature exceeds 1100 ° C., abnormal grain growth of the main phase occurs and H _cJ may decrease. The first heat treatment temperature is preferably 800 ° C. or more and 1000 ° C. or less. This is because it is possible to obtain a higher B _r and a high H _cJ. The heat treatment time is set to an appropriate value depending on the composition and dimensions of the R1-T1-Cu-B-based sintered body and R2-Ga-Co-based alloy, the heat treatment temperature, etc., but 5 minutes or more and 20 hours or less is preferable. More preferably, minutes to 15 hours and still more preferably 30 minutes to 10 hours. Moreover, it is preferable to prepare 2 mass% or more and 30 mass% or less of R2-Ga-Co type alloy with respect to the weight of R1-T1-Cu-B type sintered compact. If the amount of the R2-Ga-Co-based alloy is less than 2 mass% with respect to the weight of the R1-T1-Cu-B-based sintered body, _HcJ may be reduced. On the other hand, there is a possibility that the B _r decreases exceeds 30 mass%.

  The first heat treatment can be performed by disposing an R2-Ga-Co-based alloy having an arbitrary shape on the surface of the R1-T1-Cu-B-based sintered body and using a known heat treatment apparatus. For example, the first heat treatment can be performed by covering the surface of the R1-T1-Cu-B-based sintered body with a powder layer of an R2-Ga-Co-based alloy. For example, after applying a slurry in which an R2-Ga-Co alloy is dispersed in a dispersion medium to the surface of an R1-T1-Cu-B sintered body, the dispersion medium is evaporated to form an R2-Ga-Co alloy and the like. You may make R1-T1-Cu-B type sintered compact contact. In addition, as shown in the experimental example described later, the R2-Ga-Co based alloy may be arranged to be in contact with the surface perpendicular to the orientation direction of at least the R1-T1-Cu-B based sintered body. preferable. In addition, alcohol (ethanol etc.), NMP (N-methyl pyrrolidone), an aldehyde, and a ketone can be illustrated as a dispersion medium. Moreover, you may perform well-known machining, such as a cutting | disconnection and cutting, with respect to the R1-T1-Cu-B type | system | group sintered compact in which 1st heat processing was implemented.

(Step of carrying out the second heat treatment)
The R1-T1-Cu-B-based sintered body subjected to the first heat treatment is subjected to heat treatment at a temperature of 450 ° C. or more and 600 ° C. or less in a vacuum or an inert gas atmosphere. In the present disclosure, this heat treatment is referred to as a second heat treatment. By performing the second heat treatment, it is possible to obtain a high B _r and high H _cJ. When the temperature of the second heat treatment is less than 450 ° C. and more than 600 ° C., the amount of R-T-Ga phase (typically, R ₆ T ₁₃ Z phase (Z is at least one of Cu and Ga)) There is a possibility that high B _r and high H _cJ can not be obtained due to too little. The second heat treatment temperature is preferably 480 ° C. or more and 560 ° C. or less. Higher H _cJ can be obtained. The heat treatment time is set to an appropriate value according to the composition and dimensions of the R1-T1-Cu-B sintered body, the heat treatment temperature, etc., preferably 5 minutes to 20 hours and more preferably 10 minutes to 15 hours. More preferably, 30 minutes or more and 10 hours or less.

In the above R ₆ T ₁₃ Z phase (R ₆ T ₁₃ Z compound), R is at least one rare earth element and necessarily includes at least one of Pr and Nd, and T is at least one transition metal element. Yes Fe must be included. The R ₆ T ₁₃ Z compound is typically an Nd ₆ Fe ₁₃ Ga compound. Further, the R ₆ T ₁₃ Z compound has a La ₆ Co ₁₁ Ga ₃ type crystal structure. The R ₆ T ₁₃ Z compound may be an R ₆ T _{13 −} δZ ₁₊ δ compound depending on the state. When relatively large amounts of Cu, Al, and Si are contained in the RTB-based sintered magnet, R ₆ T _13- δ (Ga _{1 -abc} Cu _a Al _b Si _c ) 1 ₊ δ It may have been.

  The R-T-B-based sintered magnet obtained by the step of performing the second heat treatment described above is subjected to known surface treatment such as plating for imparting corrosion resistance or performing known machining such as cutting or cutting. It can be performed. In addition, the RTB-based sintered magnet obtained by the production method of the present disclosure is characterized in that at least one of Fe or Co, Al, Mn, Si and Fe in the RTB-based sintered magnet and T2 ( The molar ratio of T2 to B ([T2] / [B]) is more than 14.0, and R, Fe, B, and Cu correspond to T1 in the R1-T1-Cu-B-based sintered body. And Ga are contained. In addition to R, Fe, B, Cu, Ga, Co, Al, Ag, In, Sn, Zr, Nb, Ti, Ni, Hf, Ta, W, Ge, Mo, V, Y, La, Ce, Sm, Ca, Mg, Mn, Si, Cr, H, F, P, S, Cl, O, N, C and the like may be contained.

<Example of First Embodiment>
The present invention will be described in more detail by way of examples, but the present invention is not limited thereto.

Experimental Example 1
[Step of preparing R1-T1-B based sintered body]
Each element is weighed so that the R1-T1-B sintered body is approximately 1-A in Table 1, and cast by a strip casting method to obtain a flake-like material alloy having a thickness of 0.2 to 0.4 mm. The After the obtained flake-like raw material alloy was subjected to hydrogen grinding, it was heated in vacuum to 550 ° C. and then dehydrogenated to cool, thereby obtaining roughly crushed powder. Next, 0.04 mass% of zinc stearate as a lubricant is added to the obtained coarsely pulverized powder with respect to 100 mass% of the roughly pulverized powder and mixed, and then nitrogen is added using an air flow crusher (jet mill apparatus) It was dry-pulverized in an air stream to obtain a finely pulverized powder (alloy powder) having a particle diameter D50 of 4 μm. The particle diameter D ₅₀ is the volume center value obtained by the laser diffraction method by air flow dispersion method (volume-based median diameter).

  After adding and mixing 0.05 mass% of zinc stearate as a lubricant with respect to 100 mass% of the finely pulverized powder to the finely pulverized powder, the mixture is molded in a magnetic field to obtain a compact. As a forming apparatus, a so-called perpendicular magnetic field forming apparatus (transverse magnetic field forming apparatus) in which the magnetic field application direction and the pressing direction are orthogonal to each other was used.

The obtained compact was sintered for 4 hours in vacuum at 1030 ° C. (the temperature at which densification due to sintering sufficiently occurs was selected) and then quenched to obtain an R1-T1-B-based sintered body. The density of the obtained sintered body was 7.5 Mg / m ³ or more. The results of the components of the obtained sintered body are shown in Table 1. Each component in Table 1 was measured using high frequency inductively coupled plasma emission spectrometry (ICP-OES). In addition, as a result of measuring the oxygen amount of a sintered compact by the gas melting-infrared absorption method, it confirmed that it was all around 0.2 mass%. Moreover, as a result of measuring C (carbon content) using the gas analyzer by the combustion-infrared absorption method, it confirmed that it was around 0.1 mass%. “[T1] / [B]” in Table 1 is obtained by dividing the analysis value (mass%) by the atomic weight of each element with respect to each element (here, Fe, Al, Si, Mn) constituting T1. The ratio (a / b) of the sum of those values (a) and the value (mass%) of B analyzed divided by the atomic weight of B (b). The same is true for all the following tables. In addition, even if it adds each composition of Table 1, the amount of oxygen, and the amount of carbon, it does not become 100 mass%. This is because, as described above, the analysis method differs depending on each component. The same applies to the other tables.

[Step of preparing R2-Ga-Cu-Co based alloy]
Each element is weighed so that R2-Ga-Cu-Co alloy has a composition of 1-a to 1-g in Table 2 approximately, the raw materials are dissolved, and single roll super-quenching method (melt spinning method ) Gave a ribbon or flake-like alloy. The obtained alloy was ground in an argon atmosphere using a mortar, and then passed through a sieve having an opening of 425 μm to prepare an R 2 -Ga-Cu-Co-based alloy. The composition of the obtained R2-Ga-Cu-Co based alloy is shown in Table 2. In addition, each component in Table 2 was measured using high frequency inductively coupled plasma emission spectrometry (ICP-OES).

[Step of carrying out first heat treatment]
The R1-T1-B based sintered body of code 1-A in Table 1 is cut and cut to form a 4.4 mm × 10.0 mm × 11.0 mm rectangular solid (a surface of 10.0 mm × 11.0 mm is oriented) Perpendicular to the Next, as shown in FIG. 3, in the processing container 3 made of niobium foil, the plane perpendicular to the orientation direction (the direction of the arrow in the figure) of the R1-T1-B sintered body 1 is mainly R2-. In order to be in contact with the Ga-Cu-Co alloy 2, the R2-Ga-Cu-Co alloy of the symbols 1-a to 1-g shown in Table 2 is R-T1-B sintered with the symbol 1-A. A total of 20 mass% of 10 mass% each was placed above and below the body with respect to the weight of the R1-T1-B-based sintered body. Next, R2-Ga-Cu-Co alloys and R1-T1-B alloys are fired at the temperature and time shown in the first heat treatment of Table 3 in vacuum argon controlled at 200 Pa using a tubular flow air furnace. The body was heated to carry out the first heat treatment and then cooled.

[Step of carrying out second heat treatment]
R1-T1-B system in which the first heat treatment was carried out at the temperature and time shown in the second heat treatment of Table 3 in a reduced pressure argon atmosphere where the second heat treatment was controlled to 200 Pa using a tubular flow air furnace It cooled after implementing with respect to the sintered compact. In order to remove the concentrated part of the R2-Ga-Cu-Co based alloy existing near the surface of each sample after heat treatment, the entire surface of each sample is cut using a surface grinder, and 4.0 mm × 4. A cubic sample (R-T-B based sintered magnet) of 0 mm × 4.0 mm was obtained. Note that the heating temperature of the R2-Ga-Cu-Co alloy and the R1-T1-B sintered body in the step of performing the first heat treatment, and R1-T1-B in the step of performing the second heat treatment The heating temperature of the sintered body was measured by attaching a thermocouple.

[sample test]
The obtained samples were measured for B _r and H _cJ of the obtained samples by B-H tracer. The measurement results are shown in Table 3. As Table 3, the present invention examples of the Co content is less than 10 mass% ultra 45Mass% of R2-Cu-Ga-Fe-based alloy it can be seen that the high B _r and a high H _cJ are achieved. On the other hand, the amount of Co in the R2-Ga-Cu-Co alloy is 10 mass% or less, and the sample No. 1 in which the content of Co <the content of Ga is satisfied. 1-1 and 1-2 do not have high _Br . Moreover, the amount of Co of the R2-Cu-Ga-Co alloy exceeds 45 mass%, and the sample No. 1 in which the content of Pr <the content of Co is satisfied. 1-7 does not obtain high H _cJ .

Experimental Example 2
[Step of preparing R1-T1-B based sintered body]
A sintered body was produced in the same manner as in Experimental Example 1 except that each element was weighed so that the R1-T1-B-based sintered body had a composition as indicated by the symbol 2-A in Table 4. Sintering was performed in the range of 1000 ° C. or more and 1050 ° C. or less (selecting the temperature at which densification by sintering sufficiently occurs for each sample). The density of the obtained sintered body was 7.5 Mg / m ³ or more. The results of the components of the obtained sintered body are shown in Table 4. Each component in Table 4 was measured by the same method as Experimental Example 1. In addition, as a result of measuring the oxygen amount of a sintered compact by the gas melting-infrared absorption method, it confirmed that it was all around 0.2 mass%. Moreover, as a result of measuring C (carbon content) using the gas analyzer by the combustion-infrared absorption method, it confirmed that it was around 0.1 mass%.

[Step of preparing R2-Ga-Cu-Co based alloy]
R2-Ga-Cu- in the same manner as in Experimental Example 1 except that each element is weighed such that the R2-Ga-Cu-Co alloy has a composition as shown by symbols 2-a to 2-m in Table 5. A Co-based alloy was prepared. The composition of the R2-Ga-Cu-Co alloy is shown in Table 5. Each component in Table 5 was measured by the same method as Experimental Example 1.

[Step of carrying out first heat treatment]
The first heat treatment was conducted in the same manner as in Experimental Example 1 except that the R2-Ga-Cu-Co based alloy and the R1-T1-B based sintered body were heated at the temperature and time shown in the first heat treatment of Table 6. Carried out.

[Step of carrying out second heat treatment]
A second heat treatment was conducted in the same manner as in Experimental Example 1 except that the R2-Ga-Cu-Co alloy and the R1-T1-B sintered body were heated at the temperature and time shown in the second heat treatment of Table 6. Carried out. Each sample after heat treatment was processed in the same manner as in Experimental Example 1 to obtain an RTB-based sintered magnet.

[sample test]
The obtained sample of B _r and H _cJ was measured by B-H tracer. The measurement results are shown in Table 6. As shown in Table 6, the R2 content of the R2-Ga-Cu-Co alloy is 35 mass% to less than 85 mass%, the Ga content is 2.5 mass% to 30 mass%, the Cu content is 2.5 mass% to 20 mass%, and the present invention examples in a composition satisfying the inequality of content> content of Co> content of Ga> content of Cu of R2 it is found that a high B _r and a high H _cJ are achieved. On the other hand, any one of R, Cu, and Ga in the R2-Ga-Cu-Co alloy is out of the range of the present disclosure (for sample Nos. 2-1 and 2-3, R2 and Co are out of the range; 2-4, 2-6, and 2-12 are out of the range of Ga, sample Nos. 2-7 and 2-9 are out of the range of Cu, and sample No. 2-13 is out of the range of Cu and Ga) Or the content of R2> the content of Co> the content of Ga> the composition not satisfying the inequality of the content of Cu (sample No. 2-8 is the content of Ga <content of Cu, sample No. 2 If -10 is the content of Co <the content of Ga), high H _cJ can not be obtained. Thus, the content of R, Cu, Ga (and Co as shown in Experimental Example 1) of the R2-Ga-Cu-Co alloy is within the range of the present disclosure, and the content of R2> the content of Co by having a composition satisfying the formula of the content of an amount> the content of Ga> Cu, it is possible to obtain a high B _r and a high H _cJ.

Experimental Example 3
[Step of preparing R1-T1-B based sintered body]
A sintered body was produced in the same manner as in Experimental Example 1 except that each element was weighed so that the R1-T1-B-based sintered body had a composition as indicated by the symbol 3-A in Table 7. Sintering was performed in the range of 1000 ° C. or more and 1050 ° C. or less (selecting the temperature at which densification by sintering sufficiently occurs for each sample). The density of the obtained sintered body was 7.5 Mg / m ³ or more. The results of the components of the obtained sintered body are shown in Table 7. Each component in Table 7 was measured by the same method as Experimental example 1. In addition, as a result of measuring the oxygen amount of a sintered compact by the gas melting-infrared absorption method, it confirmed that it was all around 0.2 mass%. Moreover, as a result of measuring C (carbon content) using the gas analyzer by the combustion-infrared absorption method, it confirmed that it was around 0.1 mass%.

[Step of preparing R2-Ga-Cu-Co based alloy]
The R2-Ga-Cu-Co alloy is prepared in the same manner as in Experimental Example 1 except that each element is weighed so that the R2-Ga-Cu-Co alloy has a composition as shown by the symbol 3-a in Table 8. Got ready. Table 8 shows the composition of the R2-Ga-Cu-Co alloy. Each component in Table 8 was measured by the same method as Experimental Example 1.

[Step of carrying out first heat treatment]
The first heat treatment was conducted in the same manner as in Experimental Example 1 except that the R2-Ga-Cu-Co based alloy and the R1-T1-B based sintered body were heated at the temperature and time shown in the first heat treatment of Table 9. Carried out.

[Step of carrying out second heat treatment]
The second heat treatment was conducted in the same manner as in Experimental Example 1 except that the R2-Ga-Cu-Co alloy and the R1-T1-B sintered body were heated at the temperature and time shown in the second heat treatment of Table 9. Carried out. Each sample after heat treatment was processed in the same manner as in Experimental Example 1 to obtain an RTB-based sintered magnet.

[sample test]
The obtained sample of B _r and H _cJ was measured by B-H tracer. The measurement results are shown in Table 9. As shown in Table 9, the first heat treatment temperature (700 ° C. or higher 1100 ° C. or less) and the present invention embodiment is a second heat treatment temperature (450 ° C. or higher 600 ° C. or less) of the present disclosure is higher B _r and a high H _cJ is obtained It is understood that it is being done. Further, as shown in Table 9, a further higher _HcJ is obtained when the temperature in the first heat treatment is 800 ° C. or more and 1000 ° C. or less and the temperature in the second heat treatment is 480 ° C. or more and 560 ° C. or less. On the other hand, either the first heat treatment temperature or the second heat treatment temperature is out of the range of the present disclosure (the sample No. 3-1 is out of the range of the first heat treatment, the sample Nos. 3-4 and 3-9 are If the second heat treatment is out of the range, high H _cJ can not be obtained.

<Example of Second Embodiment>
Experimental Example 4
[Step of preparing R1-T1-Cu-B based sintered body]
Each element is weighed so that R1-T1-Cu-B based sintered body is approximately 4-A to 4-E in Table 10 and cast by a strip casting method, and flakes having a thickness of 0.2 to 0.4 mm The raw material alloy was obtained. After the obtained flake-like raw material alloy was subjected to hydrogen grinding, it was heated in vacuum to 550 ° C. and then dehydrogenated to cool, thereby obtaining roughly crushed powder. Next, 0.04 mass% of zinc stearate as a lubricant is added to the obtained coarsely pulverized powder with respect to 100 mass% of the roughly pulverized powder and mixed, and then nitrogen is added using an air flow crusher (jet mill apparatus) dry milled in an air stream, the particle size D ₅₀ was obtained finely pulverized powder of 4μm (the alloy powder). The particle diameter D ₅₀ is the volume center value obtained by the laser diffraction method by air flow dispersion method (volume-based median diameter).

  After adding and mixing 0.05 mass% of zinc stearate as a lubricant with respect to 100 mass% of the finely pulverized powder to the finely pulverized powder, the mixture is molded in a magnetic field to obtain a compact. As a forming apparatus, a so-called perpendicular magnetic field forming apparatus (transverse magnetic field forming apparatus) in which the magnetic field application direction and the pressing direction are orthogonal to each other was used.

The resulting compact is sintered for 4 hours in vacuum at 1000 ° C. or more and 1050 ° C. or less (select the temperature at which densification by sintering sufficiently occurs for each sample), and then quench it, R1-T1-B based sintering I got a body. The density of the obtained sintered body was 7.5 Mg / m ³ or more. The results of the components of the obtained sintered body are shown in Table 10. Each component in Table 10 was measured using high frequency inductively coupled plasma emission spectrometry (ICP-OES). In addition, as a result of measuring the oxygen amount of a sintered compact by the gas melting-infrared absorption method, it confirmed that it was all around 0.2 mass%. Moreover, as a result of measuring C (carbon content) using the gas analyzer by the combustion-infrared absorption method, it confirmed that it was around 0.1 mass%. “[T1] / [B]” in Table 10 is obtained by dividing the analysis value (mass%) by the atomic weight of each element with respect to each element (here, Fe, Al, Si, Mn) constituting T1. The ratio (a / b) of the sum of those values (a) and the value (mass%) of B analyzed divided by the atomic weight of B (b). The same is true for all the following tables. In addition, even if it adds each composition of Table 10, the amount of oxygen, and the amount of carbon, it does not become 100 mass%. This is because, as described above, the analysis method differs depending on each component. The same applies to the other tables.

[Step of preparing R2-Ga-Co based alloy]
Each element is weighed so that the R2-Ga-Co based alloy has a composition as shown by symbol 4-a in Table 11, and the raw materials thereof are melted to obtain ribbons or flakes by a single roll super-quenching method (melt spinning method). An alloy of the shape of a circle is obtained. The obtained alloy was ground in an argon atmosphere using a mortar, and then passed through a sieve having an opening of 425 μm to prepare an R 2 -Ga-Co based alloy. The composition of the obtained R2-Ga-Co alloy is shown in Table 11. In addition, each component in Table 11 was measured using high frequency inductively coupled plasma emission spectrometry (ICP-OES).

[Step of carrying out first heat treatment]
The R1-T1-Cu-B based sintered body of the code 4-A to 4-E in Table 10 is cut and cut to form a rectangular solid (10.0 mm × 11.4) of 4.4 mm × 10.0 mm × 11.0 mm. A plane of 0 mm was a plane perpendicular to the orientation direction). Next, as shown in FIG. 3, in the processing container 3 made of niobium foil, a plane perpendicular to the orientation direction (the direction of the arrow in the figure) of the R1-T1-Cu-B sintered body 1 is mainly The R2-Ga-Co-based alloy of 4-a shown in Table 11 is burned with R1-T1-Cu-B-based 4-A to 4-E so as to be in contact with the R2-Ga-Co-based alloy 2. A total of 20 mass% of 10 mass% each was arranged above and below the body with respect to the weight of the R1-T1-Cu-B-based sintered body. Next, R2-Ga-Co alloys and R1-T1-Cu-B alloys are fired at the temperature and time shown in the first heat treatment of Table 12 in vacuum argon controlled at 200 Pa using a tubular flow air furnace. The body was heated to carry out the first heat treatment and then cooled.

[Step of carrying out second heat treatment]
R1-T1-B system in which the first heat treatment was carried out at a temperature and for a time shown in the second heat treatment of Table 12 in a reduced pressure argon atmosphere where the second heat treatment was controlled to 200 Pa using a tubular flow air furnace It cooled after implementing with respect to the sintered compact. In order to remove the concentrated part of R2-Ga-Co based alloy existing near the surface of each sample after heat treatment, the entire surface of each sample is cut using a surface grinder, 4.0 mm × 4.0 mm × A cube-shaped sample (R-T-B-based sintered magnet) of 4.0 mm was obtained. Note that the heating temperature of the R2-Ga-Co alloy and the R1-T1-Cu-B-based sintered body in the step of performing the first heat treatment, and R1-T1-Cu- in the step of performing the second heat treatment. The heating temperature of the B-based sintered body was measured by attaching a thermocouple.

[sample test]
Each sample of B _r and H _cJ obtained was measured by B-H tracer. The measurement results are shown in Table 12. As shown in Table 12, sample No. 1 in which the Cu content of the R1-T1-Cu-B-based sintered body is less than 0.1 mass%. 4-1 does not have high H _cJ . In addition, sample No. 1 in which the content of Cu exceeds 1.5 mass%. 4-5 does not obtain a high B _r and H _cJ.

Experimental Example 5
[Step of preparing R1-T1-Cu-B based sintered body]
A sintered body was produced in the same manner as in Experimental Example 4 except that each element was weighed so that the R1-T1-Cu-B-based sintered body had a composition as indicated by the symbol 5-A in Table 13. The density of the obtained sintered body was 7.5 Mg / m ³ or more. The results of the components of the obtained sintered body are shown in Table 13. Each component in Table 13 was measured by the same method as Experimental Example 4. In addition, as a result of measuring the oxygen amount of a sintered compact by the gas melting-infrared absorption method, it confirmed that it was all around 0.2 mass%. Moreover, as a result of measuring C (carbon content) using the gas analyzer by the combustion-infrared absorption method, it confirmed that it was around 0.1 mass%.

[Step of preparing R2-Ga-Co based alloy]
The R2-Ga-Co alloy is prepared in the same manner as in Experimental Example 4 except that each element is weighed so that the R2-Ga-Co alloy has a composition as shown by symbols 5-a to 5-g in Table 14. Got ready. The composition of the R2-Ga-Co based alloy is shown in Table 14. Each component in Table 14 was measured by the same method as Experimental Example 4.

[Step of carrying out first heat treatment]
The first heat treatment is performed in the same manner as in Experimental Example 4 except that the R2-Ga-Co alloy and the R1-T1-Cu-B sintered body are heated at the temperature and time shown in the first heat treatment of Table 15. did.

[Step of carrying out second heat treatment]
The second heat treatment is performed in the same manner as in Experimental Example 4 except that the R2-Ga-Co alloy and the R1-T1-Cu-B-based sintered body are heated at the temperature and time shown in the second heat treatment of Table 15 did. Each sample after heat treatment was processed in the same manner as in Experimental Example 4 to obtain an RTB-based sintered magnet.

[sample test]
Each sample of B _r and H _cJ obtained was measured by B-H tracer. The measurement results are shown in Table 15. As Table 15, the present invention example Co amount of R-Ga-Co-based alloy is at most 10 mass% ultra 45Mass% It can be seen that the high B _r and a high H _cJ are achieved. On the other hand, Sample No. 1 in which the Co content of the R-Ga-Co based alloy is 10 mass% or less and the content of Co <Ga content. 5-1 and 5-2 are not high B _r is obtained. Moreover, the amount of Co of the R-Ga-Co alloy exceeds 45 mass%, and the sample No. 1 in which the content of Pr <the content of Co is satisfied. In 5-7, high H _cJ is not obtained.

Experimental Example 6
[Step of preparing R1-T1-Cu-B based sintered body]
A sintered body was produced in the same manner as in Experimental Example 4 except that each element was weighed so that the R1-T1-Cu-B-based sintered body had a composition approximately as indicated by symbol 6-A in Table 16. The density of the obtained sintered body was 7.5 Mg / m ³ or more. The results of the components of the obtained sintered body are shown in Table 16. Each component in Table 16 was measured by the same method as Experimental Example 4. In addition, as a result of measuring the oxygen amount of a sintered compact by the gas melting-infrared absorption method, it confirmed that it was all around 0.2 mass%. Moreover, as a result of measuring C (carbon content) using the gas analyzer by the combustion-infrared absorption method, it confirmed that it was around 0.1 mass%.

[Step of preparing R2-Ga-Co based alloy]
The R2-Ga-Co alloy is prepared in the same manner as in Experimental Example 4 except that each element is weighed so that the R2-Ga-Co alloy has a composition as shown by symbols 6-a to 6-i in Table 17. Got ready. The composition of the R2-Ga-Co based alloy is shown in Table 17. Each component in Table 17 was measured by the same method as Experimental Example 4.

[Step of carrying out first heat treatment]
The first heat treatment is performed in the same manner as in Experimental Example 4 except that the R2-Ga-Co alloy and the R1-T1-Cu-B sintered body are heated at the temperature and time shown in the first heat treatment of Table 18 did.

[Step of carrying out second heat treatment]
The second heat treatment is performed in the same manner as in Experimental Example 4 except that the R2-Ga-Co alloy and the R1-T1-Cu-B sintered body are heated at the temperature and time shown in the second heat treatment of Table 18 did. Each sample after heat treatment was processed in the same manner as in Experimental Example 4 to obtain an RTB-based sintered magnet.

[sample test]
Each sample of B _r and H _cJ obtained was measured by B-H tracer. The measurement results are shown in Table 18. As shown in Table 18, R2 content of R2-Ga-Co alloy is 35 mass% or more and 87 mass% or less, Ga content is 2.5 mass% or more and 30 mass% or less, and R2 content> Co content> Ga content the present invention examples in a composition satisfying the inequality is seen that a high B _r and a high H _cJ are achieved. On the other hand, any one of R and Ga in the R2-Ga-Co alloy is out of the range of the present disclosure (sample No. 6-1 has R2 out of the range, sample No. 6-3 has R2 and Co out of the range Sample Nos. 6-4, 6-6, and 6-9 have a composition that does not satisfy the inequality in which Ga is out of the range or R2 content> Co content> Ga content inequality (Sample No. 6) If -7 is the content of Co <the content of Ga), high H _cJ can not be obtained. Thus, the content of R and Ga (and Co as shown in Experimental Example 5) of the R2-Ga-Cu-Co alloy is within the range of the present disclosure, and the content of R2> the content of Co> by a composition satisfying the inequality of the content of Ga, it is possible to obtain a high B _r and a high H _cJ.

Experimental Example 7
[Step of preparing R1-T1-B based sintered body]
A sintered body was produced in the same manner as in Experimental Example 4 except that each element was weighed so that the R1-T1-B-based sintered body had a composition approximately as indicated by symbol 7-A in Table 19. The density of the obtained sintered body was 7.5 Mg / m ³ or more. The results of the components of the obtained sintered body are shown in Table 19. Each component in Table 19 was measured by the same method as Experimental Example 4. In addition, as a result of measuring the oxygen amount of a sintered compact by the gas melting-infrared absorption method, it confirmed that it was all around 0.2 mass%. Moreover, as a result of measuring C (carbon content) using the gas analyzer by the combustion-infrared absorption method, it confirmed that it was around 0.1 mass%.

[Step of preparing R2-Ga-Co based alloy]
An R2-Ga-Co-based alloy was prepared in the same manner as in Experimental Example 4 except that each element was weighed so that the R2-Ga-Co-based alloy had a composition shown by the symbol 7-a in Table 20. The composition of the R2-Ga-Co based alloy is shown in Table 20. Each component in Table 20 was measured by the same method as Experimental Example 4.

[Step of carrying out first heat treatment]
The first heat treatment is performed in the same manner as in Experimental Example 4 except that the R2-Ga-Co alloy and the R1-T1-Cu-B sintered body are heated at the temperature and time shown in the first heat treatment of Table 21. did.

[Step of carrying out second heat treatment]
The second heat treatment is performed in the same manner as in Experimental Example 4 except that the R2-Ga-Co alloy and the R1-T1-Cu-B sintered body are heated at the temperature and time shown in the second heat treatment of Table 21. did. Each sample after heat treatment was processed in the same manner as in Experimental Example 4 to obtain an RTB-based sintered magnet.

[sample test]
The obtained sample was measured B _r and H _cJ of the sample by B-H tracer. The measurement results are shown in Table 21. As Table 21, the first heat treatment temperature (700 ° C. or higher 1100 ° C. or less) and the present invention embodiment is a second heat treatment temperature (450 ° C. or higher 600 ° C. or less) of the present disclosure is higher B _r and a high H _cJ is obtained It is understood that it is being done. Further, as shown in Table 21, a further higher _HcJ is obtained when the temperature in the first heat treatment is 800 ° C. or more and 1000 ° C. or less and the temperature in the second heat treatment is 480 ° C. or more and 560 ° C. or less. On the other hand, either the first heat treatment temperature or the second heat treatment temperature is out of the range of the present disclosure (the sample No. 7-1 is out of the range of the first heat treatment, the sample Nos. 7-4 and 7-9 are If the second heat treatment is out of the range, high H _cJ can not be obtained.

  The RTB-based sintered magnet obtained according to the present disclosure includes various motors such as a voice coil motor (VCM) for a hard disk drive, a motor for electric vehicles (EV, HV, PHV, etc.), a motor for industrial equipment, It can be suitably used for home appliances and the like.

1 R1-T1-B based sintered body (R1-T1-Cu-B based sintered body)
2 R2-Ga-Cu-Co based alloy (R2-Ga-Co based alloy)
3 treatment vessel 12 main phase 14 grain boundary phase 14a double grain grain boundary phase 14b grain boundary triple point

Claims (16)

Preparing an R1-T1-B-based sintered body;
Preparing an R2-Ga-Cu-Co alloy;
At least a portion of the R2-Ga-Cu-Co alloy is brought into contact with at least a portion of the surface of the R1-T1-B sintered body, and the temperature is 700 ° C. or more and 1100 ° C. or less in a vacuum or inert gas atmosphere. Carrying out a first heat treatment at a temperature of
Performing a second heat treatment on the R1-T1-B-based sintered body subjected to the first heat treatment in a vacuum or an inert gas atmosphere at a temperature of 450 ° C. or more and 600 ° C. or less;
Including
In the R1-T1-B based sintered body,
R1 is at least one of rare earth elements and always contains at least one of Nd and Pr, and the content of R1 is 27 mass% or more and 35 mass% or less of the entire R1-T1-B sintered body,
T1 is at least one selected from the group consisting of Fe, Co, Al, Mn, and Si, T1 necessarily contains Fe, and the content of Fe with respect to the entire T1 is 80 mass% or more,
The molar ratio of T1 to B ([T1] / [B]) is more than 14.0 and not more than 15.0,
In the R2-Ga-Cu-Co alloy,
R2 is at least one of rare earth elements and necessarily contains at least one of Nd and Pr, and the content of R2 is 35 mass% or more and less than 85 mass% of the entire R2-Ga-Cu-Co alloy,
The content of Ga is 2.5 mass% or more and 30 mass% or less of the entire R2-Ga-Cu-Co alloy,
The content of Cu is 2.5 mass% or more and 20 mass% or less of the entire R2-Ga-Cu-Co alloy,
The content of Co is more than 10% by mass and 45% by mass or less of the entire R2-Ga-Cu-Co alloy,
Content of R2> Content of Co> Content of Ga> The manufacturing method of the R-T-B type sintered magnet in which the inequality of the content of Cu is materialized.   The manufacturing method of the RTB-based sintered magnet according to claim 1, wherein the molar ratio of T1 to B ([T1] / [B]) is 14.5 or more and 15.0 or less.   The manufacturing method of the RTB based sintered magnet according to claim 1 or 2, wherein 50 mass% or more of R2 in the R2-Ga-Cu-Co based alloy is Pr.   The manufacturing method of the RTB based sintered magnet according to claim 1 or 2, wherein 70 mass% or more of R2 in the R2-Ga-Cu-Co based alloy is Pr.   The R-T-B-based sintered magnet according to any one of claims 1 to 4, wherein the total content of R2-Ga-Cu-Co in the R2-Ga-Cu-Co alloy is 80 mass% or more. Production method.   The manufacturing method of the RTB-based sintered magnet according to any one of claims 1 to 5, wherein a temperature in the first heat treatment is 800 ° C or more and 1000 ° C or less.   The manufacturing method of the RTB-based sintered magnet according to any one of claims 1 to 6, wherein the temperature in the second heat treatment is 480 ° C or more and 560 ° C or less. The step of preparing the R1-T1-B-based sintered body includes pulverizing the raw material alloy to a particle diameter D ₅₀ of 3 μm or more and 10 μm or less, and then performing orientation and sintering in a magnetic field. 7. The manufacturing method of the RTB-based sintered magnet according to any one of 7 to 10. Preparing an R1-T1-Cu-B sintered body;
Preparing an R2-Ga-Co based alloy;
At least a part of the R2-Ga-Co alloy is brought into contact with at least a part of the surface of the R1-T1-Cu-B sintered body, and the temperature is 700 ° C. or more and 1100 ° C. or less in a vacuum or inert gas atmosphere. Carrying out a first heat treatment at a temperature of
Performing a second heat treatment on the R1-T1-Cu-B-based sintered body subjected to the first heat treatment at a temperature of 450 ° C. to 600 ° C. in a vacuum or an inert gas atmosphere; ,
Including
In the R1-T1-Cu-B-based sintered body,
R1 is at least one of rare earth elements and always contains at least one of Nd and Pr, and the content of R1 is 27 mass% or more and 35 mass% or less of the entire R1-T1-Cu-B sintered body,
T1 is at least one selected from the group consisting of Fe, Co, Al, Mn, and Si, T1 necessarily contains Fe, and the content of Fe with respect to the entire T1 is 80 mass% or more,
The molar ratio of T1 to B ([T1] / [B]) is more than 14.0 and not more than 15.0,
The content of Cu is 0.1 mass% or more and 1.5 mass% or less of the entire R1-T1-Cu-B-based sintered body,
In the R2-Ga-Co based alloy,
R2 is at least one of rare earth elements and necessarily contains at least one of Nd and Pr, and the content of R2 is 35 mass% or more and less than 87 mass% of the entire R2-Ga-Co alloy,
The content of Ga is 2.5 mass% or more and 30 mass% or less of the entire R2-Ga-Co alloy,
The content of Co is more than 10 mass% and 45 mass% or less of the entire R2-Ga-Co alloy,
R2 content> Co content> Ga content inequality holds,
The manufacturing method of RTB type sintered magnet.   The manufacturing method of the RTB-based sintered magnet according to claim 9, wherein a molar ratio of T1 to B ([T1] / [B]) is 14.3 or more and 15.0 or less.   The manufacturing method of the RTB-based sintered magnet according to claim 9 or 10, wherein 50 mass% or more of R2 in the R2-Ga-Co-based alloy is Pr.   The manufacturing method of the RTB based sintered magnet according to claim 9 or 10, wherein 70 mass% or more of R2 in the R2-Ga-Co based alloy is Pr.   The manufacturing method of the RTB-based sintered magnet according to any one of claims 9 to 12, wherein a total content of R2, Ga and Co in the R2-Ga-Co-based alloy is 80 mass% or more.   The method for producing an RTB-based sintered magnet according to any one of claims 9 to 13, wherein a temperature in the first heat treatment is 800 ° C to 1000 ° C.   The method for producing an RTB-based sintered magnet according to any one of claims 9 to 14, wherein a temperature in the second heat treatment is 480 ° C or more and 560 ° C or less. Preparing the R1-T1-Cu-B based sintered body comprises performing after the material alloy particle size D ₅₀ was pulverized to 3μm or 10μm or less, the sintering being oriented in a magnetic field, wherein Item 16. A method for producing an R-T-B-based sintered magnet according to any one of items 9 to 15.

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